JP2000024902A - Hand grinding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the sealing action of a grinding spindle bearing and to improve the service life by comprising an annular gap for accommodating the reserve of the fluid paste medium. SOLUTION: A lower spindle bearing 28 downwardly directed in the axial direction is supported by an end wall 33 radially retracted inwardly on the midst of a bearing flange 32. An axial upward end wall 33 supports a seal ring 34 formed as a radial waveform seal ring from its back surface. A same type second seal ring 36 is arranged to the seal ring at a specified interval in the axial direction. An annular chamber between the seal rings 34, 36 is filled with the fluid paste medium. The medium is useful as a dust barrier, and couples and holds the dust moving toward the lower bearing 28 along the grinding spindle 26. The end surfaces differently shaped like a mirror image, of the seal rings 34, 36 are opposite to one another.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hand-held grinding machine, and more particularly to a concrete grinder formed as an angle grinder, in particular, provided with a casing comprising a motor casing and a transmission casing. It houses a motor and a transmission with a grinding spindle, in particular consisting of a bevel pinion and a bevel gear, the grinding spindle being rotatably mounted on a bearing in the casing, in particular on a bearing flange. A sealing means, in particular a cover disk, is axially pre-mounted on at least one of the bearings,
The sealing means relates to a casing, in particular of the type in which the bearing flange is shielded from the grinding spindle.

[0002]

BACKGROUND OF THE INVENTION Published German Patent Application No. 195
A hand-held grinding machine designed as a concrete grinder is known from DE 03201. This grinding machine is a disk-shaped tool for processing stone and concrete surfaces, for example, for post-processing of facades, for deburring concrete edges, breaking edges, removing irregularities, etc. And a protective hood with

A circular surface of a grinding wheel of a concrete grinder contacts a surface to be processed. In this case, dust is remarkably generated. This dust generation is limited to the immediate vicinity of the tool inside the cover hood, for example, by an annular brush strip arranged on the edge of the protective hood on the end side. Such a seal allows the negative pressure to have a pumping action under the protective hood during a dust removal operation. This pumping action transports the dust towards the lower grinding spindle bearing.

In the case of this known concrete grinder, when the grinding tool is mounted on a work surface with a large area, as is conventional, a fluctuating strong bending force acts on the lower area of the grinding spindle. This causes a certain wobbling movement of the lower grinding spindle area, which results in a further dust transport action. Thus, despite the new seals, especially with the fluctuating negative pressure on the lower side of the protective hood, dust entrapment in the transmission casing or in the lower grinding spindle bearings is reduced, It is still inconvenient.

[0005]

It is an object of the present invention to obviate the above-mentioned disadvantages.

[0006]

SUMMARY OF THE INVENTION In order to solve this problem, according to the present invention, between the bearing and the previously mounted sealing means, another sealing means for sealing the casing to the grinding spindle is provided. It is arranged with a particularly annular gap for receiving a reservoir of the fluid-paste medium.

[0007]

The concrete grinder according to the invention has the advantage that the sealing effect of the lower grinding spindle bearing is improved, thereby significantly increasing the service life.

Since the bearing and the sealing means having a gap are arranged in the bearing flange of the transmission casing, a compact structure of the sealing member is made possible, especially as a component group.

The bearing flange has a flat end wall which is radially retracted on the inside, said end wall being for the bearing on the side facing the bearing and on the side facing the sealing means. For the sealing means, an arrangement is provided which can be easily assembled by serving as a stop.

The sealing means is formed as a radial wavy sealing ring, and the deformed sides of these radial wavy sealing rings face each other at a predetermined distance in the axial direction. By forming an annular gap that tightly accommodates the medium of the shape,
A particularly dense dust barrier is provided.

Due to the fact that the sealing means are non-rotatably arranged on the bearing flange, this bearing flange is particularly effectively sealed against the ingress of dust or the outflow of a fluid-paste medium.

The grinding spindle receives the bevel gear on the opposite side of the collar in an axially fixed and defined arrangement, so that the grinding spindle comprises a bearing flange and sealing means, in particular a paste-fluid medium. The formation of one component together with the bearing and the bearing allows a particularly simple and accurate assembly of the hand-held grinding machine.

The front end of the assembly is provided without grinding spindles and bevel gears, since the bearing is axially fixed on the bearing flange on the upper side by means of a position-locking ring.

The medium can be easily replaced or replenished by the bearing flange supporting at least one through-opening communicating between the seal rings from the outside radially inward.

The fact that the through-opening can be sealed by means of a threaded pin allows this through-opening to be easily opened for replenishment of the medium.

The front-end dust barrier is provided by the fact that the sealing disc is hat-shaped and whose outer edge region is spaced such that it has a minimum gap with respect to the end face of the bearing flange. . Due to the centrifugal action of the rotating sealing disc, this dust barrier significantly reduces the amount of dust reaching the radial sealing ring. To this end, the shape and arrangement of the sealing disk assists in the re-emission of dust particles reaching from the lower periphery to the radial sealing ring.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention shown in the drawings will be described.

A hand-held grinding machine 10 formed as a concrete grinder has a motor casing 12. This motor casing is flanged to the transmission casing 14. Motor casing 12
Has a motor 16 formed as an electric motor, and the transmission casing 14 has an orthogonal transmission 19. The orthogonal transmission comprises a bevel pinion 20 which is mounted on a motor shaft 18 so as not to rotate. This bevel pinion is in mesh with the bevel gear 22. The bevel pinion 20 is axially fixed by a pinion nut 24 and is non-rotatably held at the free end of the motor shaft 18, while the bevel gear 22 is connected to the motor casing 12.
And surrounds and engages a grinding spindle 26 disposed at a right angle thereto. The grinding spindle comprises a lower spindle bearing 28 and an upper spindle bearing 30.
And rotatably mounted on the transmission casing 14 via

The lower spindle bearing 28 is held axially upward by a position fixing ring 29 (FIG. 2) and is mounted on its outer ring to a cylindrical bearing flange 32, also called a neck, The inner spindle (not shown) is used to rotate the grinding spindle 2 so that it cannot rotate.
6 surrounding and engaged therewith. Downward in the axial direction, the lower spindle bearing 28 is supported by an end wall 33 that is drawn inward in the radial direction in the middle of the bearing flange 32.

Toward the upper side in the axial direction, a seal ring 34 formed as a radially corrugated seal ring is supported on a back surface 64 of the end wall 33. The same second seal ring 36 is arranged at a predetermined interval in the axial direction with respect to this seal ring. Double seal ring 3
An annular chamber 38 is located between 4 and 36. This annular chamber is filled with a fluid paste-like medium 39. This media serves as a dust barrier and binds and adheres to dust that has moved along the grinding spindle 26 toward the lower bearing 28. The seal rings 34, 36 are mirror-imaged to one another and face each other at their irregularly shaped end faces 58.

On the lower end surface of the bearing flange 32, a seal disk 40 formed in a hat shape or a dish shape in the axial direction is supported by its flange-shaped edge. This sealing disc is oriented at its bottom towards the sealing rings 34,36. The seal disk 40 has an outer diameter substantially the same as the bearing flange 32, ie, the neck. The grinding spindle 26 penetrates a middle through portion 40 ′ (FIG. 3) provided at the bottom of the seal disk 40, and the grinding spindle fixes the position of the seal disk 40 in the axial direction by a stepped flange 27. The seal disk 40 is fixed so as not to rotate. The seal disk 40 forms an annular gap with the bearing flange 32.

Toward the lower side in the axial direction, the flange 27 has another assembling flange 4 formed as a two-sided portion (Zweiflach) 43.
2 follow with a larger diameter. A support flange 44 is supported on the assembling flange in the axial direction upward to support the grinding wheel 46 in the axial direction.
The grinding wheel 46 is fastened axially upwardly to the support flange 44 by a locknut 48 via an external thread 26 'formed at the lower free end of the grinding spindle.

The grinding spindle 26 has a two-sided portion 43 on an assembling flange 42. The two sides can be held by a wrench for assembly purposes.

The neck or bearing flange 32 is surrounded on the outside by a mounting opening of a bell-shaped protective hood 50. The protective hood can be screwed in the axial direction to the shoulder 31 of the bearing flange 32 by means not shown.

The lower edge of the protective hood 50 is the brush ring 5
2 is supported. This brush ring prevents the grinding dust from coming out.

FIG. 2 shows a bearing flange 32 with a grinding spindle 26. This grinding spindle 26
Penetrates through the lower grinding spindle bearing 28, the seal rings 34, 36, the paste flowing medium 39 held between these seal rings, and the seal disk 40 to form one component group. are doing. As is particularly evident, the position fixing ring 29, the sealing disc 40,
Two holes 55 communicating between the two seal rings 34 and 36 on the side facing in the radial direction are provided. Each of these holes supports one threaded pin 56.
Through these holes, paste-fluid medium 39 can be replenished between seal rings 34,36. This is because these holes lead directly to the locations where the sealing rings 34, 36 meet on the end faces.

FIG. 3 is a diagram showing the components shown in FIG. 2 spatially separated from each other. The aforementioned features and the profiled end face 58 of one of the seal rings 34, 36 and the rear face 64 of the other seal ring are evident.

FIG. 4 shows a view from above of one of the seal rings 34, 36 provided with a view of the end face 58 which is shaped differently. The end face forms an annular chamber for accommodating the medium 39 in a paste flow state by the annular groove 62 and the concave portion 60 in the axial and radial directions. Further, the inner edges of the seal rings 34 and 36 are
It is clear that it has 6,68. These seal lips are connected to the grinding spindle 26 and the seal ring 3
4 and 36 to prevent dust from entering.

FIG. 5 is a cross-sectional view of one of the seal rings 34, 36. A smooth back surface 6 of this sealing ring, through which two annular grooves (not shown) pass.
4, the end face 58 formed in an irregular shape, and the sealing lip 6
6, 68 are clearly provided.

FIG. 6 is a side view of the seal rings 34 and 36. What is particularly clear is that axial and radial recesses 60 in the end face 58 are provided.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view of a concrete grinder according to the present invention.

FIG. 2 is a longitudinal sectional view of a bearing flange according to the present invention.

FIG. 3 is an exploded view of the bearing flange shown in FIG. 2;

FIG. 4 is a plan view of one radial corrugated seal ring.

FIG. 5 is a side view of one radial corrugated seal ring.

FIG. 6 is a longitudinal sectional view of one radial corrugated seal ring.

[Explanation of symbols]

10 hand-held grinding machine, 12 motor casing,
14 gearbox casing, 16 motor, 18
Motor shaft, 19 orthogonal transmission, 20 bevel pinion, 22 bevel gear, 24 pinion nut,
26 grinding spindle, 26 'external thread, 27
Flange, 28, 30 spindle bearing, 29 position fixing ring, 31 shoulder, 32 bearing flange,
33 end wall, 34, 36 seal ring, 38 annular chamber, 39 medium, 40 seal disk, 40 '
Penetration, 42 Assembling flange, 43 Two-sided, 44
Support flange, 46 grinding wheel, 48 lock nut,
50 protective hood, 52 brush ring, 55
Holes, 56 threaded pins, 58 end faces, 60
Recess, 62 annular groove, 64 back, 66, 68
Seal lip

Continued on the front page (72) Inventor Michael Mörk Germany Rheinfelden-E Hitterdingen Asternweg 20 (72) Inventor Theo Turkscherer Germany Gaildorf Karl Sbader Strasse 5

Claims (10)

[Claims] 1. A hand-held grinding machine (10) provided with a casing (12, 14), the casing comprising a motor (16) and a transmission (19) with a grinding spindle (26). And the grinding spindle is mounted in bearings (28, 3) in the casing (12, 14).
0), wherein at least one of the bearings (28) is pre-mounted in the axial direction with a sealing means (40), said sealing means comprising a casing (1).
2, 14) to the grinding spindle (26), wherein between the bearing (28) and the pre-mounted sealing means (40), the casing (12, 14) is provided with a grinding spindle. (2
6) another sealing means (34, 36) for sealing against
Are arranged with a gap (38) for containing a reservoir of a fluid-paste medium (39). 2. The bearing flange (32) has a gap (3).
8) supporting the sealing means (34, 36) with the bearing (28) of the transmission casing (14);
The hand-held grinding machine according to claim 1. 3. The bearing flange (32) has a flat end wall (33) which is radially retracted on the inside, said end wall being on the side facing the bearing (28) for the bearing. And the sealing means (34, 36, 40), on the side facing the sealing means (34, 36, 40), serves as an axial stop for the sealing means and forms an annular gap with the grinding spindle (26). Or a hand-held grinding machine according to 2. 4. The sealing means (34, 36) is formed as a radially corrugated sealing ring, and the deformed end faces (58) of these sealing means face each other to form a fluid paste. 2. The hand-held grinding machine according to claim 1, wherein the annular gap (38) is filled with a medium (39). 5. A hand-held grinding machine according to claim 1, wherein the sealing means (34, 36) are non-rotatably arranged on the bearing flange (32). 6. The bevel gear (22) is received on a side opposite to the collar (27) with the grinding spindle (26) fixedly and non-rotatably arranged at a prescribed axial distance. By doing so, the grinding spindle (26) is brought into contact with the bearing flange (32) and the sealing means (34, 36, 4).
2. The hand-held grinding machine according to claim 1, wherein the component group is formed together with the bearings and the bearings. 7. A bearing (28) having a position fixing ring (2).
2. The hand-held grinding machine according to claim 1, wherein the machine is axially fixed to the bearing flange (32) by (9). 8. The bearing according to claim 1, wherein the bearing flange supports at least one closable radial through-opening (55), said through-opening communicating between the sealing rings (34, 36). Hand held grinding machine. 9. The at least one through opening (55).
2. The hand-held grinding machine according to claim 1, wherein the seal is sealable by a threaded pin (56) or a pushable sphere or the like. 10. A hand-held grinding machine according to claim 1, wherein the bearing flange (32) supports a protective hood (50).